Abstract: In order to explore the relationship between the lipid peroxidation and endothelin（ET）,prostacyclin（PGI₂）released by endothelial ce1ls,lipidperoxidation was induced with cumene hydrioeroxide in cultured human endothelial cells.The content of ET and PGI₂ in supernatant of cultured endothelial cells were measured by a specific radioimmunoassay.The results showed that lipid peroxide could damage the vascular endothelial cells,leading to the release of ET and the decrease in the PGI₂ synthesis.